A humanitarian crisis is looming in the Gaza Strip, after a new wave of Israeli-Palestinian fighting. Robert Berger reports from the VOA bureau in Jerusalem.

Palestinian refugees who came to pick up food at a United Nations agency in Gaza were turned away empty handed. Some 20-thousand people were due to pick up packages containing rice, flour, sugar and oil but the warehouses are empty.

The reason: Israel shut its border crossings into Gaza 11 days ago in response to Palestinian rocket attacks.

U.N. spokesman Chris Gunness said the rocket attacks are intolerable.

"Of course Israel has legitimate security concerns and we respect that and we respect the right and indeed the obligation of Israel to take action."

But Gunness said that is not a justification for cutting off food supplies, and he demanded that the borders reopen immediately.

"Let's see this for what it is. Fifty-six percent of the Gaza Strip are children. Let us not cause suffering of innocent children."

Violence erupted 11 days ago when Israel launched a cross-border raid into Gaza that it said was necessary to prevent the kidnapping of Israeli soldiers. The Islamic militant group Hamas that rules Gaza responded with rocket and mortar attacks. The fighting has brought a five-month-old ceasefire to the brink of collapse.